diff options
Diffstat (limited to 'linux-2.6-xen-sparse/mm/mmap.c')
| -rw-r--r-- | linux-2.6-xen-sparse/mm/mmap.c | 2093 |
1 files changed, 0 insertions, 2093 deletions
diff --git a/linux-2.6-xen-sparse/mm/mmap.c b/linux-2.6-xen-sparse/mm/mmap.c deleted file mode 100644 index 191c8ad3ec..0000000000 --- a/linux-2.6-xen-sparse/mm/mmap.c +++ /dev/null @@ -1,2093 +0,0 @@ -/* - * mm/mmap.c - * - * Written by obz. - * - * Address space accounting code <alan@redhat.com> - */ - -#include <linux/slab.h> -#include <linux/mm.h> -#include <linux/shm.h> -#include <linux/mman.h> -#include <linux/pagemap.h> -#include <linux/swap.h> -#include <linux/syscalls.h> -#include <linux/capability.h> -#include <linux/init.h> -#include <linux/file.h> -#include <linux/fs.h> -#include <linux/personality.h> -#include <linux/security.h> -#include <linux/hugetlb.h> -#include <linux/profile.h> -#include <linux/module.h> -#include <linux/mount.h> -#include <linux/mempolicy.h> -#include <linux/rmap.h> - -#include <asm/uaccess.h> -#include <asm/cacheflush.h> -#include <asm/tlb.h> - -#ifndef arch_mmap_check -#define arch_mmap_check(addr, len, flags) (0) -#endif - -static void unmap_region(struct mm_struct *mm, - struct vm_area_struct *vma, struct vm_area_struct *prev, - unsigned long start, unsigned long end); - -/* - * WARNING: the debugging will use recursive algorithms so never enable this - * unless you know what you are doing. - */ -#undef DEBUG_MM_RB - -/* description of effects of mapping type and prot in current implementation. - * this is due to the limited x86 page protection hardware. The expected - * behavior is in parens: - * - * map_type prot - * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC - * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes - * w: (no) no w: (no) no w: (yes) yes w: (no) no - * x: (no) no x: (no) yes x: (no) yes x: (yes) yes - * - * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes - * w: (no) no w: (no) no w: (copy) copy w: (no) no - * x: (no) no x: (no) yes x: (no) yes x: (yes) yes - * - */ -pgprot_t protection_map[16] = { - __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, - __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 -}; - -int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ -int sysctl_overcommit_ratio = 50; /* default is 50% */ -int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; -atomic_t vm_committed_space = ATOMIC_INIT(0); - -/* - * Check that a process has enough memory to allocate a new virtual - * mapping. 0 means there is enough memory for the allocation to - * succeed and -ENOMEM implies there is not. - * - * We currently support three overcommit policies, which are set via the - * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting - * - * Strict overcommit modes added 2002 Feb 26 by Alan Cox. - * Additional code 2002 Jul 20 by Robert Love. - * - * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. - * - * Note this is a helper function intended to be used by LSMs which - * wish to use this logic. - */ -int __vm_enough_memory(long pages, int cap_sys_admin) -{ - unsigned long free, allowed; - - vm_acct_memory(pages); - - /* - * Sometimes we want to use more memory than we have - */ - if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) - return 0; - - if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { - unsigned long n; - - free = global_page_state(NR_FILE_PAGES); - free += nr_swap_pages; - - /* - * Any slabs which are created with the - * SLAB_RECLAIM_ACCOUNT flag claim to have contents - * which are reclaimable, under pressure. The dentry - * cache and most inode caches should fall into this - */ - free += atomic_read(&slab_reclaim_pages); - - /* - * Leave the last 3% for root - */ - if (!cap_sys_admin) - free -= free / 32; - - if (free > pages) - return 0; - - /* - * nr_free_pages() is very expensive on large systems, - * only call if we're about to fail. - */ - n = nr_free_pages(); - - /* - * Leave reserved pages. The pages are not for anonymous pages. - */ - if (n <= totalreserve_pages) - goto error; - else - n -= totalreserve_pages; - - /* - * Leave the last 3% for root - */ - if (!cap_sys_admin) - n -= n / 32; - free += n; - - if (free > pages) - return 0; - - goto error; - } - - allowed = (totalram_pages - hugetlb_total_pages()) - * sysctl_overcommit_ratio / 100; - /* - * Leave the last 3% for root - */ - if (!cap_sys_admin) - allowed -= allowed / 32; - allowed += total_swap_pages; - - /* Don't let a single process grow too big: - leave 3% of the size of this process for other processes */ - allowed -= current->mm->total_vm / 32; - - /* - * cast `allowed' as a signed long because vm_committed_space - * sometimes has a negative value - */ - if (atomic_read(&vm_committed_space) < (long)allowed) - return 0; -error: - vm_unacct_memory(pages); - - return -ENOMEM; -} - -EXPORT_SYMBOL(__vm_enough_memory); - -/* - * Requires inode->i_mapping->i_mmap_lock - */ -static void __remove_shared_vm_struct(struct vm_area_struct *vma, - struct file *file, struct address_space *mapping) -{ - if (vma->vm_flags & VM_DENYWRITE) - atomic_inc(&file->f_dentry->d_inode->i_writecount); - if (vma->vm_flags & VM_SHARED) - mapping->i_mmap_writable--; - - flush_dcache_mmap_lock(mapping); - if (unlikely(vma->vm_flags & VM_NONLINEAR)) - list_del_init(&vma->shared.vm_set.list); - else - vma_prio_tree_remove(vma, &mapping->i_mmap); - flush_dcache_mmap_unlock(mapping); -} - -/* - * Unlink a file-based vm structure from its prio_tree, to hide - * vma from rmap and vmtruncate before freeing its page tables. - */ -void unlink_file_vma(struct vm_area_struct *vma) -{ - struct file *file = vma->vm_file; - - if (file) { - struct address_space *mapping = file->f_mapping; - spin_lock(&mapping->i_mmap_lock); - __remove_shared_vm_struct(vma, file, mapping); - spin_unlock(&mapping->i_mmap_lock); - } -} - -/* - * Close a vm structure and free it, returning the next. - */ -static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) -{ - struct vm_area_struct *next = vma->vm_next; - - might_sleep(); - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); - if (vma->vm_file) - fput(vma->vm_file); - mpol_free(vma_policy(vma)); - kmem_cache_free(vm_area_cachep, vma); - return next; -} - -asmlinkage unsigned long sys_brk(unsigned long brk) -{ - unsigned long rlim, retval; - unsigned long newbrk, oldbrk; - struct mm_struct *mm = current->mm; - - down_write(&mm->mmap_sem); - - if (brk < mm->end_code) - goto out; - - /* - * Check against rlimit here. If this check is done later after the test - * of oldbrk with newbrk then it can escape the test and let the data - * segment grow beyond its set limit the in case where the limit is - * not page aligned -Ram Gupta - */ - rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; - if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) - goto out; - - newbrk = PAGE_ALIGN(brk); - oldbrk = PAGE_ALIGN(mm->brk); - if (oldbrk == newbrk) - goto set_brk; - - /* Always allow shrinking brk. */ - if (brk <= mm->brk) { - if (!do_munmap(mm, newbrk, oldbrk-newbrk)) - goto set_brk; - goto out; - } - - /* Check against existing mmap mappings. */ - if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) - goto out; - - /* Ok, looks good - let it rip. */ - if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) - goto out; -set_brk: - mm->brk = brk; -out: - retval = mm->brk; - up_write(&mm->mmap_sem); - return retval; -} - -#ifdef DEBUG_MM_RB -static int browse_rb(struct rb_root *root) -{ - int i = 0, j; - struct rb_node *nd, *pn = NULL; - unsigned long prev = 0, pend = 0; - - for (nd = rb_first(root); nd; nd = rb_next(nd)) { - struct vm_area_struct *vma; - vma = rb_entry(nd, struct vm_area_struct, vm_rb); - if (vma->vm_start < prev) - printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; - if (vma->vm_start < pend) - printk("vm_start %lx pend %lx\n", vma->vm_start, pend); - if (vma->vm_start > vma->vm_end) - printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); - i++; - pn = nd; - } - j = 0; - for (nd = pn; nd; nd = rb_prev(nd)) { - j++; - } - if (i != j) - printk("backwards %d, forwards %d\n", j, i), i = 0; - return i; -} - -void validate_mm(struct mm_struct *mm) -{ - int bug = 0; - int i = 0; - struct vm_area_struct *tmp = mm->mmap; - while (tmp) { - tmp = tmp->vm_next; - i++; - } - if (i != mm->map_count) - printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; - i = browse_rb(&mm->mm_rb); - if (i != mm->map_count) - printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; - BUG_ON(bug); -} -#else -#define validate_mm(mm) do { } while (0) -#endif - -static struct vm_area_struct * -find_vma_prepare(struct mm_struct *mm, unsigned long addr, - struct vm_area_struct **pprev, struct rb_node ***rb_link, - struct rb_node ** rb_parent) -{ - struct vm_area_struct * vma; - struct rb_node ** __rb_link, * __rb_parent, * rb_prev; - - __rb_link = &mm->mm_rb.rb_node; - rb_prev = __rb_parent = NULL; - vma = NULL; - - while (*__rb_link) { - struct vm_area_struct *vma_tmp; - - __rb_parent = *__rb_link; - vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); - - if (vma_tmp->vm_end > addr) { - vma = vma_tmp; - if (vma_tmp->vm_start <= addr) - return vma; - __rb_link = &__rb_parent->rb_left; - } else { - rb_prev = __rb_parent; - __rb_link = &__rb_parent->rb_right; - } - } - - *pprev = NULL; - if (rb_prev) - *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); - *rb_link = __rb_link; - *rb_parent = __rb_parent; - return vma; -} - -static inline void -__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, - struct vm_area_struct *prev, struct rb_node *rb_parent) -{ - if (prev) { - vma->vm_next = prev->vm_next; - prev->vm_next = vma; - } else { - mm->mmap = vma; - if (rb_parent) - vma->vm_next = rb_entry(rb_parent, - struct vm_area_struct, vm_rb); - else - vma->vm_next = NULL; - } -} - -void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, - struct rb_node **rb_link, struct rb_node *rb_parent) -{ - rb_link_node(&vma->vm_rb, rb_parent, rb_link); - rb_insert_color(&vma->vm_rb, &mm->mm_rb); -} - -static inline void __vma_link_file(struct vm_area_struct *vma) -{ - struct file * file; - - file = vma->vm_file; - if (file) { - struct address_space *mapping = file->f_mapping; - - if (vma->vm_flags & VM_DENYWRITE) - atomic_dec(&file->f_dentry->d_inode->i_writecount); - if (vma->vm_flags & VM_SHARED) - mapping->i_mmap_writable++; - - flush_dcache_mmap_lock(mapping); - if (unlikely(vma->vm_flags & VM_NONLINEAR)) - vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); - else - vma_prio_tree_insert(vma, &mapping->i_mmap); - flush_dcache_mmap_unlock(mapping); - } -} - -static void -__vma_link(struct mm_struct *mm, struct vm_area_struct *vma, - struct vm_area_struct *prev, struct rb_node **rb_link, - struct rb_node *rb_parent) -{ - __vma_link_list(mm, vma, prev, rb_parent); - __vma_link_rb(mm, vma, rb_link, rb_parent); - __anon_vma_link(vma); -} - -static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, - struct vm_area_struct *prev, struct rb_node **rb_link, - struct rb_node *rb_parent) -{ - struct address_space *mapping = NULL; - - if (vma->vm_file) - mapping = vma->vm_file->f_mapping; - - if (mapping) { - spin_lock(&mapping->i_mmap_lock); - vma->vm_truncate_count = mapping->truncate_count; - } - anon_vma_lock(vma); - - __vma_link(mm, vma, prev, rb_link, rb_parent); - __vma_link_file(vma); - - anon_vma_unlock(vma); - if (mapping) - spin_unlock(&mapping->i_mmap_lock); - - mm->map_count++; - validate_mm(mm); -} - -/* - * Helper for vma_adjust in the split_vma insert case: - * insert vm structure into list and rbtree and anon_vma, - * but it has already been inserted into prio_tree earlier. - */ -static void -__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) -{ - struct vm_area_struct * __vma, * prev; - struct rb_node ** rb_link, * rb_parent; - - __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); - BUG_ON(__vma && __vma->vm_start < vma->vm_end); - __vma_link(mm, vma, prev, rb_link, rb_parent); - mm->map_count++; -} - -static inline void -__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, - struct vm_area_struct *prev) -{ - prev->vm_next = vma->vm_next; - rb_erase(&vma->vm_rb, &mm->mm_rb); - if (mm->mmap_cache == vma) - mm->mmap_cache = prev; -} - -/* - * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that - * is already present in an i_mmap tree without adjusting the tree. - * The following helper function should be used when such adjustments - * are necessary. The "insert" vma (if any) is to be inserted - * before we drop the necessary locks. - */ -void vma_adjust(struct vm_area_struct *vma, unsigned long start, - unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) -{ - struct mm_struct *mm = vma->vm_mm; - struct vm_area_struct *next = vma->vm_next; - struct vm_area_struct *importer = NULL; - struct address_space *mapping = NULL; - struct prio_tree_root *root = NULL; - struct file *file = vma->vm_file; - struct anon_vma *anon_vma = NULL; - long adjust_next = 0; - int remove_next = 0; - - if (next && !insert) { - if (end >= next->vm_end) { - /* - * vma expands, overlapping all the next, and - * perhaps the one after too (mprotect case 6). - */ -again: remove_next = 1 + (end > next->vm_end); - end = next->vm_end; - anon_vma = next->anon_vma; - importer = vma; - } else if (end > next->vm_start) { - /* - * vma expands, overlapping part of the next: - * mprotect case 5 shifting the boundary up. - */ - adjust_next = (end - next->vm_start) >> PAGE_SHIFT; - anon_vma = next->anon_vma; - importer = vma; - } else if (end < vma->vm_end) { - /* - * vma shrinks, and !insert tells it's not - * split_vma inserting another: so it must be - * mprotect case 4 shifting the boundary down. - */ - adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); - anon_vma = next->anon_vma; - importer = next; - } - } - - if (file) { - mapping = file->f_mapping; - if (!(vma->vm_flags & VM_NONLINEAR)) - root = &mapping->i_mmap; - spin_lock(&mapping->i_mmap_lock); - if (importer && - vma->vm_truncate_count != next->vm_truncate_count) { - /* - * unmap_mapping_range might be in progress: - * ensure that the expanding vma is rescanned. - */ - importer->vm_truncate_count = 0; - } - if (insert) { - insert->vm_truncate_count = vma->vm_truncate_count; - /* - * Put into prio_tree now, so instantiated pages - * are visible to arm/parisc __flush_dcache_page - * throughout; but we cannot insert into address - * space until vma start or end is updated. - */ - __vma_link_file(insert); - } - } - - /* - * When changing only vma->vm_end, we don't really need - * anon_vma lock: but is that case worth optimizing out? - */ - if (vma->anon_vma) - anon_vma = vma->anon_vma; - if (anon_vma) { - spin_lock(&anon_vma->lock); - /* - * Easily overlooked: when mprotect shifts the boundary, - * make sure the expanding vma has anon_vma set if the - * shrinking vma had, to cover any anon pages imported. - */ - if (importer && !importer->anon_vma) { - importer->anon_vma = anon_vma; - __anon_vma_link(importer); - } - } - - if (root) { - flush_dcache_mmap_lock(mapping); - vma_prio_tree_remove(vma, root); - if (adjust_next) - vma_prio_tree_remove(next, root); - } - - vma->vm_start = start; - vma->vm_end = end; - vma->vm_pgoff = pgoff; - if (adjust_next) { - next->vm_start += adjust_next << PAGE_SHIFT; - next->vm_pgoff += adjust_next; - } - - if (root) { - if (adjust_next) - vma_prio_tree_insert(next, root); - vma_prio_tree_insert(vma, root); - flush_dcache_mmap_unlock(mapping); - } - - if (remove_next) { - /* - * vma_merge has merged next into vma, and needs - * us to remove next before dropping the locks. - */ - __vma_unlink(mm, next, vma); - if (file) - __remove_shared_vm_struct(next, file, mapping); - if (next->anon_vma) - __anon_vma_merge(vma, next); - } else if (insert) { - /* - * split_vma has split insert from vma, and needs - * us to insert it before dropping the locks - * (it may either follow vma or precede it). - */ - __insert_vm_struct(mm, insert); - } - - if (anon_vma) - spin_unlock(&anon_vma->lock); - if (mapping) - spin_unlock(&mapping->i_mmap_lock); - - if (remove_next) { - if (file) - fput(file); - mm->map_count--; - mpol_free(vma_policy(next)); - kmem_cache_free(vm_area_cachep, next); - /* - * In mprotect's case 6 (see comments on vma_merge), - * we must remove another next too. It would clutter - * up the code too much to do both in one go. - */ - if (remove_next == 2) { - next = vma->vm_next; - goto again; - } - } - - validate_mm(mm); -} - -/* - * If the vma has a ->close operation then the driver probably needs to release - * per-vma resources, so we don't attempt to merge those. - */ -#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP) - -static inline int is_mergeable_vma(struct vm_area_struct *vma, - struct file *file, unsigned long vm_flags) -{ - if (vma->vm_flags != vm_flags) - return 0; - if (vma->vm_file != file) - return 0; - if (vma->vm_ops && vma->vm_ops->close) - return 0; - return 1; -} - -static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, - struct anon_vma *anon_vma2) -{ - return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2); -} - -/* - * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) - * in front of (at a lower virtual address and file offset than) the vma. - * - * We cannot merge two vmas if they have differently assigned (non-NULL) - * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. - * - * We don't check here for the merged mmap wrapping around the end of pagecache - * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which - * wrap, nor mmaps which cover the final page at index -1UL. - */ -static int -can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, - struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) -{ - if (is_mergeable_vma(vma, file, vm_flags) && - is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { - if (vma->vm_pgoff == vm_pgoff) - return 1; - } - return 0; -} - -/* - * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) - * beyond (at a higher virtual address and file offset than) the vma. - * - * We cannot merge two vmas if they have differently assigned (non-NULL) - * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. - */ -static int -can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, - struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) -{ - if (is_mergeable_vma(vma, file, vm_flags) && - is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { - pgoff_t vm_pglen; - vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; - if (vma->vm_pgoff + vm_pglen == vm_pgoff) - return 1; - } - return 0; -} - -/* - * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out - * whether that can be merged with its predecessor or its successor. - * Or both (it neatly fills a hole). - * - * In most cases - when called for mmap, brk or mremap - [addr,end) is - * certain not to be mapped by the time vma_merge is called; but when - * called for mprotect, it is certain to be already mapped (either at - * an offset within prev, or at the start of next), and the flags of - * this area are about to be changed to vm_flags - and the no-change - * case has already been eliminated. - * - * The following mprotect cases have to be considered, where AAAA is - * the area passed down from mprotect_fixup, never extending beyond one - * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: - * - * AAAA AAAA AAAA AAAA - * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX - * cannot merge might become might become might become - * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or - * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or - * mremap move: PPPPNNNNNNNN 8 - * AAAA - * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN - * might become case 1 below case 2 below case 3 below - * - * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: - * mprotect_fixup updates vm_flags & vm_page_prot on successful return. - */ -struct vm_area_struct *vma_merge(struct mm_struct *mm, - struct vm_area_struct *prev, unsigned long addr, - unsigned long end, unsigned long vm_flags, - struct anon_vma *anon_vma, struct file *file, - pgoff_t pgoff, struct mempolicy *policy) -{ - pgoff_t pglen = (end - addr) >> PAGE_SHIFT; - struct vm_area_struct *area, *next; - - /* - * We later require that vma->vm_flags == vm_flags, - * so this tests vma->vm_flags & VM_SPECIAL, too. - */ - if (vm_flags & VM_SPECIAL) - return NULL; - - if (prev) - next = prev->vm_next; - else - next = mm->mmap; - area = next; - if (next && next->vm_end == end) /* cases 6, 7, 8 */ - next = next->vm_next; - - /* - * Can it merge with the predecessor? - */ - if (prev && prev->vm_end == addr && - mpol_equal(vma_policy(prev), policy) && - can_vma_merge_after(prev, vm_flags, - anon_vma, file, pgoff)) { - /* - * OK, it can. Can we now merge in the successor as well? - */ - if (next && end == next->vm_start && - mpol_equal(policy, vma_policy(next)) && - can_vma_merge_before(next, vm_flags, - anon_vma, file, pgoff+pglen) && - is_mergeable_anon_vma(prev->anon_vma, - next->anon_vma)) { - /* cases 1, 6 */ - vma_adjust(prev, prev->vm_start, - next->vm_end, prev->vm_pgoff, NULL); - } else /* cases 2, 5, 7 */ - vma_adjust(prev, prev->vm_start, - end, prev->vm_pgoff, NULL); - return prev; - } - - /* - * Can this new request be merged in front of next? - */ - if (next && end == next->vm_start && - mpol_equal(policy, vma_policy(next)) && - can_vma_merge_before(next, vm_flags, - anon_vma, file, pgoff+pglen)) { - if (prev && addr < prev->vm_end) /* case 4 */ - vma_adjust(prev, prev->vm_start, - addr, prev->vm_pgoff, NULL); - else /* cases 3, 8 */ - vma_adjust(area, addr, next->vm_end, - next->vm_pgoff - pglen, NULL); - return area; - } - - return NULL; -} - -/* - * find_mergeable_anon_vma is used by anon_vma_prepare, to check - * neighbouring vmas for a suitable anon_vma, before it goes off - * to allocate a new anon_vma. It checks because a repetitive - * sequence of mprotects and faults may otherwise lead to distinct - * anon_vmas being allocated, preventing vma merge in subsequent - * mprotect. - */ -struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) -{ - struct vm_area_struct *near; - unsigned long vm_flags; - - near = vma->vm_next; - if (!near) - goto try_prev; - - /* - * Since only mprotect tries to remerge vmas, match flags - * which might be mprotected into each other later on. - * Neither mlock nor madvise tries to remerge at present, - * so leave their flags as obstructing a merge. - */ - vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); - vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); - - if (near->anon_vma && vma->vm_end == near->vm_start && - mpol_equal(vma_policy(vma), vma_policy(near)) && - can_vma_merge_before(near, vm_flags, - NULL, vma->vm_file, vma->vm_pgoff + - ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT))) - return near->anon_vma; -try_prev: - /* - * It is potentially slow to have to call find_vma_prev here. - * But it's only on the first write fault on the vma, not - * every time, and we could devise a way to avoid it later - * (e.g. stash info in next's anon_vma_node when assigning - * an anon_vma, or when trying vma_merge). Another time. - */ - BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma); - if (!near) - goto none; - - vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); - vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); - - if (near->anon_vma && near->vm_end == vma->vm_start && - mpol_equal(vma_policy(near), vma_policy(vma)) && - can_vma_merge_after(near, vm_flags, - NULL, vma->vm_file, vma->vm_pgoff)) - return near->anon_vma; -none: - /* - * There's no absolute need to look only at touching neighbours: - * we could search further afield for "compatible" anon_vmas. - * But it would probably just be a waste of time searching, - * or lead to too many vmas hanging off the same anon_vma. - * We're trying to allow mprotect remerging later on, - * not trying to minimize memory used for anon_vmas. - */ - return NULL; -} - -#ifdef CONFIG_PROC_FS -void vm_stat_account(struct mm_struct *mm, unsigned long flags, - struct file *file, long pages) -{ - const unsigned long stack_flags - = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); - - if (file) { - mm->shared_vm += pages; - if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) - mm->exec_vm += pages; - } else if (flags & stack_flags) - mm->stack_vm += pages; - if (flags & (VM_RESERVED|VM_IO)) - mm->reserved_vm += pages; -} -#endif /* CONFIG_PROC_FS */ - -/* - * The caller must hold down_write(current->mm->mmap_sem). - */ - -unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, - unsigned long len, unsigned long prot, - unsigned long flags, unsigned long pgoff) -{ - struct mm_struct * mm = current->mm; - struct vm_area_struct * vma, * prev; - struct inode *inode; - unsigned int vm_flags; - int correct_wcount = 0; - int error; - struct rb_node ** rb_link, * rb_parent; - int accountable = 1; - unsigned long charged = 0, reqprot = prot; - - if (file) { - if (is_file_hugepages(file)) - accountable = 0; - - if (!file->f_op || !file->f_op->mmap) - return -ENODEV; - - if ((prot & PROT_EXEC) && - (file->f_vfsmnt->mnt_flags & MNT_NOEXEC)) - return -EPERM; - } - /* - * Does the application expect PROT_READ to imply PROT_EXEC? - * - * (the exception is when the underlying filesystem is noexec - * mounted, in which case we dont add PROT_EXEC.) - */ - if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) - if (!(file && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))) - prot |= PROT_EXEC; - - if (!len) - return -EINVAL; - - error = arch_mmap_check(addr, len, flags); - if (error) - return error; - - /* Careful about overflows.. */ - len = PAGE_ALIGN(len); - if (!len || len > TASK_SIZE) - return -ENOMEM; - - /* offset overflow? */ - if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) - return -EOVERFLOW; - - /* Too many mappings? */ - if (mm->map_count > sysctl_max_map_count) - return -ENOMEM; - - /* Obtain the address to map to. we verify (or select) it and ensure - * that it represents a valid section of the address space. - */ - addr = get_unmapped_area(file, addr, len, pgoff, flags); - if (addr & ~PAGE_MASK) - return addr; - - /* Do simple checking here so the lower-level routines won't have - * to. we assume access permissions have been handled by the open - * of the memory object, so we don't do any here. - */ - vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | - mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; - - if (flags & MAP_LOCKED) { - if (!can_do_mlock()) - return -EPERM; - vm_flags |= VM_LOCKED; - } - /* mlock MCL_FUTURE? */ - if (vm_flags & VM_LOCKED) { - unsigned long locked, lock_limit; - locked = len >> PAGE_SHIFT; - locked += mm->locked_vm; - lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; - lock_limit >>= PAGE_SHIFT; - if (locked > lock_limit && !capable(CAP_IPC_LOCK)) - return -EAGAIN; - } - - inode = file ? file->f_dentry->d_inode : NULL; - - if (file) { - switch (flags & MAP_TYPE) { - case MAP_SHARED: - if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) - return -EACCES; - - /* - * Make sure we don't allow writing to an append-only - * file.. - */ - if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) - return -EACCES; - - /* - * Make sure there are no mandatory locks on the file. - */ - if (locks_verify_locked(inode)) - return -EAGAIN; - - vm_flags |= VM_SHARED | VM_MAYSHARE; - if (!(file->f_mode & FMODE_WRITE)) - vm_flags &= ~(VM_MAYWRITE | VM_SHARED); - - /* fall through */ - case MAP_PRIVATE: - if (!(file->f_mode & FMODE_READ)) - return -EACCES; - break; - - default: - return -EINVAL; - } - } else { - switch (flags & MAP_TYPE) { - case MAP_SHARED: - vm_flags |= VM_SHARED | VM_MAYSHARE; - break; - case MAP_PRIVATE: - /* - * Set pgoff according to addr for anon_vma. - */ - pgoff = addr >> PAGE_SHIFT; - break; - default: - return -EINVAL; - } - } - - error = security_file_mmap(file, reqprot, prot, flags); - if (error) - return error; - - /* Clear old maps */ - error = -ENOMEM; -munmap_back: - vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); - if (vma && vma->vm_start < addr + len) { - if (do_munmap(mm, addr, len)) - return -ENOMEM; - goto munmap_back; - } - - /* Check against address space limit. */ - if (!may_expand_vm(mm, len >> PAGE_SHIFT)) - return -ENOMEM; - - if (accountable && (!(flags & MAP_NORESERVE) || - sysctl_overcommit_memory == OVERCOMMIT_NEVER)) { - if (vm_flags & VM_SHARED) { - /* Check memory availability in shmem_file_setup? */ - vm_flags |= VM_ACCOUNT; - } else if (vm_flags & VM_WRITE) { - /* - * Private writable mapping: check memory availability - */ - charged = len >> PAGE_SHIFT; - if (security_vm_enough_memory(charged)) - return -ENOMEM; - vm_flags |= VM_ACCOUNT; - } - } - - /* - * Can we just expand an old private anonymous mapping? - * The VM_SHARED test is necessary because shmem_zero_setup - * will create the file object for a shared anonymous map below. - */ - if (!file && !(vm_flags & VM_SHARED) && - vma_merge(mm, prev, addr, addr + len, vm_flags, - NULL, NULL, pgoff, NULL)) - goto out; - - /* - * Determine the object being mapped and call the appropriate - * specific mapper. the address has already been validated, but - * not unmapped, but the maps are removed from the list. - */ - vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); - if (!vma) { - error = -ENOMEM; - goto unacct_error; - } - - vma->vm_mm = mm; - vma->vm_start = addr; - vma->vm_end = addr + len; - vma->vm_flags = vm_flags; - vma->vm_page_prot = protection_map[vm_flags & - (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; - vma->vm_pgoff = pgoff; - - if (file) { - error = -EINVAL; - if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) - goto free_vma; - if (vm_flags & VM_DENYWRITE) { - error = deny_write_access(file); - if (error) - goto free_vma; - correct_wcount = 1; - } - vma->vm_file = file; - get_file(file); - error = file->f_op->mmap(file, vma); - if (error) - goto unmap_and_free_vma; - } else if (vm_flags & VM_SHARED) { - error = shmem_zero_setup(vma); - if (error) - goto free_vma; - } - - /* Don't make the VMA automatically writable if it's shared, but the - * backer wishes to know when pages are first written to */ - if (vma->vm_ops && vma->vm_ops->page_mkwrite) - vma->vm_page_prot = - protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC)]; - - /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform - * shmem_zero_setup (perhaps called through /dev/zero's ->mmap) - * that memory reservation must be checked; but that reservation - * belongs to shared memory object, not to vma: so now clear it. - */ - if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT)) - vma->vm_flags &= ~VM_ACCOUNT; - - /* Can addr have changed?? - * - * Answer: Yes, several device drivers can do it in their - * f_op->mmap method. -DaveM - */ - addr = vma->vm_start; - pgoff = vma->vm_pgoff; - vm_flags = vma->vm_flags; - - if (!file || !vma_merge(mm, prev, addr, vma->vm_end, - vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) { - file = vma->vm_file; - vma_link(mm, vma, prev, rb_link, rb_parent); - if (correct_wcount) - atomic_inc(&inode->i_writecount); - } else { - if (file) { - if (correct_wcount) - atomic_inc(&inode->i_writecount); - fput(file); - } - mpol_free(vma_policy(vma)); - kmem_cache_free(vm_area_cachep, vma); - } -out: - mm->total_vm += len >> PAGE_SHIFT; - vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); - if (vm_flags & VM_LOCKED) { - mm->locked_vm += len >> PAGE_SHIFT; - make_pages_present(addr, addr + len); - } - if (flags & MAP_POPULATE) { - up_write(&mm->mmap_sem); - sys_remap_file_pages(addr, len, 0, - pgoff, flags & MAP_NONBLOCK); - down_write(&mm->mmap_sem); - } - return addr; - -unmap_and_free_vma: - if (correct_wcount) - atomic_inc(&inode->i_writecount); - vma->vm_file = NULL; - fput(file); - - /* Undo any partial mapping done by a device driver. */ - unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); - charged = 0; -free_vma: - kmem_cache_free(vm_area_cachep, vma); -unacct_error: - if (charged) - vm_unacct_memory(charged); - return error; -} - -EXPORT_SYMBOL(do_mmap_pgoff); - -/* Get an address range which is currently unmapped. - * For shmat() with addr=0. - * - * Ugly calling convention alert: - * Return value with the low bits set means error value, - * ie - * if (ret & ~PAGE_MASK) - * error = ret; - * - * This function "knows" that -ENOMEM has the bits set. - */ -#ifndef HAVE_ARCH_UNMAPPED_AREA -unsigned long -arch_get_unmapped_area(struct file *filp, unsigned long addr, - unsigned long len, unsigned long pgoff, unsigned long flags) -{ - struct mm_struct *mm = current->mm; - struct vm_area_struct *vma; - unsigned long start_addr; - - if (len > TASK_SIZE) - return -ENOMEM; - - if (addr) { - addr = PAGE_ALIGN(addr); - vma = find_vma(mm, addr); - if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) - return addr; - } - if (len > mm->cached_hole_size) { - start_addr = addr = mm->free_area_cache; - } else { - start_addr = addr = TASK_UNMAPPED_BASE; - mm->cached_hole_size = 0; - } - -full_search: - for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { - /* At this point: (!vma || addr < vma->vm_end). */ - if (TASK_SIZE - len < addr) { - /* - * Start a new search - just in case we missed - * some holes. - */ - if (start_addr != TASK_UNMAPPED_BASE) { - addr = TASK_UNMAPPED_BASE; - start_addr = addr; - mm->cached_hole_size = 0; - goto full_search; - } - return -ENOMEM; - } - if (!vma || addr + len <= vma->vm_start) { - /* - * Remember the place where we stopped the search: - */ - mm->free_area_cache = addr + len; - return addr; - } - if (addr + mm->cached_hole_size < vma->vm_start) - mm->cached_hole_size = vma->vm_start - addr; - addr = vma->vm_end; - } -} -#endif - -void arch_unmap_area(struct mm_struct *mm, unsigned long addr) -{ - /* - * Is this a new hole at the lowest possible address? - */ - if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) { - mm->free_area_cache = addr; - mm->cached_hole_size = ~0UL; - } -} - -/* - * This mmap-allocator allocates new areas top-down from below the - * stack's low limit (the base): - */ -#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN -unsigned long -arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, - const unsigned long len, const unsigned long pgoff, - const unsigned long flags) -{ - struct vm_area_struct *vma; - struct mm_struct *mm = current->mm; - unsigned long addr = addr0; - - /* requested length too big for entire address space */ - if (len > TASK_SIZE) - return -ENOMEM; - - /* requesting a specific address */ - if (addr) { - addr = PAGE_ALIGN(addr); - vma = find_vma(mm, addr); - if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) - return addr; - } - - /* check if free_area_cache is useful for us */ - if (len <= mm->cached_hole_size) { - mm->cached_hole_size = 0; - mm->free_area_cache = mm->mmap_base; - } - - /* either no address requested or can't fit in requested address hole */ - addr = mm->free_area_cache; - - /* make sure it can fit in the remaining address space */ - if (addr > len) { - vma = find_vma(mm, addr-len); - if (!vma || addr <= vma->vm_start) - /* remember the address as a hint for next time */ - return (mm->free_area_cache = addr-len); - } - - if (mm->mmap_base < len) - goto bottomup; - - addr = mm->mmap_base-len; - - do { - /* - * Lookup failure means no vma is above this address, - * else if new region fits below vma->vm_start, - * return with success: - */ - vma = find_vma(mm, addr); - if (!vma || addr+len <= vma->vm_start) - /* remember the address as a hint for next time */ - return (mm->free_area_cache = addr); - - /* remember the largest hole we saw so far */ - if (addr + mm->cached_hole_size < vma->vm_start) - mm->cached_hole_size = vma->vm_start - addr; - - /* try just below the current vma->vm_start */ - addr = vma->vm_start-len; - } while (len < vma->vm_start); - -bottomup: - /* - * A failed mmap() very likely causes application failure, - * so fall back to the bottom-up function here. This scenario - * can happen with large stack limits and large mmap() - * allocations. - */ - mm->cached_hole_size = ~0UL; - mm->free_area_cache = TASK_UNMAPPED_BASE; - addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); - /* - * Restore the topdown base: - */ - mm->free_area_cache = mm->mmap_base; - mm->cached_hole_size = ~0UL; - - return addr; -} -#endif - -void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) -{ - /* - * Is this a new hole at the highest possible address? - */ - if (addr > mm->free_area_cache) - mm->free_area_cache = addr; - - /* dont allow allocations above current base */ - if (mm->free_area_cache > mm->mmap_base) - mm->free_area_cache = mm->mmap_base; -} - -unsigned long -get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, - unsigned long pgoff, unsigned long flags) -{ - unsigned long ret; - - if (!(flags & MAP_FIXED)) { - unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); - - get_area = current->mm->get_unmapped_area; - if (file && file->f_op && file->f_op->get_unmapped_area) - get_area = file->f_op->get_unmapped_area; - addr = get_area(file, addr, len, pgoff, flags); - if (IS_ERR_VALUE(addr)) - return addr; - } - - if (addr > TASK_SIZE - len) - return -ENOMEM; - if (addr & ~PAGE_MASK) - return -EINVAL; - if (file && is_file_hugepages(file)) { - /* - * Check if the given range is hugepage aligned, and - * can be made suitable for hugepages. - */ - ret = prepare_hugepage_range(addr, len); - } else { - /* - * Ensure that a normal request is not falling in a - * reserved hugepage range. For some archs like IA-64, - * there is a separate region for hugepages. - */ - ret = is_hugepage_only_range(current->mm, addr, len); - } - if (ret) - return -EINVAL; - return addr; -} - -EXPORT_SYMBOL(get_unmapped_area); - -/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ -struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr) -{ - struct vm_area_struct *vma = NULL; - - if (mm) { - /* Check the cache first. */ - /* (Cache hit rate is typically around 35%.) */ - vma = mm->mmap_cache; - if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { - struct rb_node * rb_node; - - rb_node = mm->mm_rb.rb_node; - vma = NULL; - - while (rb_node) { - struct vm_area_struct * vma_tmp; - - vma_tmp = rb_entry(rb_node, - struct vm_area_struct, vm_rb); - - if (vma_tmp->vm_end > addr) { - vma = vma_tmp; - if (vma_tmp->vm_start <= addr) - break; - rb_node = rb_node->rb_left; - } else - rb_node = rb_node->rb_right; - } - if (vma) - mm->mmap_cache = vma; - } - } - return vma; -} - -EXPORT_SYMBOL(find_vma); - -/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ -struct vm_area_struct * -find_vma_prev(struct mm_struct *mm, unsigned long addr, - struct vm_area_struct **pprev) -{ - struct vm_area_struct *vma = NULL, *prev = NULL; - struct rb_node * rb_node; - if (!mm) - goto out; - - /* Guard against addr being lower than the first VMA */ - vma = mm->mmap; - - /* Go through the RB tree quickly. */ - rb_node = mm->mm_rb.rb_node; - - while (rb_node) { - struct vm_area_struct *vma_tmp; - vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); - - if (addr < vma_tmp->vm_end) { - rb_node = rb_node->rb_left; - } else { - prev = vma_tmp; - if (!prev->vm_next || (addr < prev->vm_next->vm_end)) - break; - rb_node = rb_node->rb_right; - } - } - -out: - *pprev = prev; - return prev ? prev->vm_next : vma; -} - -/* - * Verify that the stack growth is acceptable and - * update accounting. This is shared with both the - * grow-up and grow-down cases. - */ -static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow) -{ - struct mm_struct *mm = vma->vm_mm; - struct rlimit *rlim = current->signal->rlim; - - /* address space limit tests */ - if (!may_expand_vm(mm, grow)) - return -ENOMEM; - - /* Stack limit test */ - if (size > rlim[RLIMIT_STACK].rlim_cur) - return -ENOMEM; - - /* mlock limit tests */ - if (vma->vm_flags & VM_LOCKED) { - unsigned long locked; - unsigned long limit; - locked = mm->locked_vm + grow; - limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; - if (locked > limit && !capable(CAP_IPC_LOCK)) - return -ENOMEM; - } - - /* - * Overcommit.. This must be the final test, as it will - * update security statistics. - */ - if (security_vm_enough_memory(grow)) - return -ENOMEM; - - /* Ok, everything looks good - let it rip */ - mm->total_vm += grow; - if (vma->vm_flags & VM_LOCKED) - mm->locked_vm += grow; - vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); - return 0; -} - -#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) -/* - * PA-RISC uses this for its stack; IA64 for its Register Backing Store. - * vma is the last one with address > vma->vm_end. Have to extend vma. - */ -#ifndef CONFIG_IA64 -static inline -#endif -int expand_upwards(struct vm_area_struct *vma, unsigned long address) -{ - int error; - - if (!(vma->vm_flags & VM_GROWSUP)) - return -EFAULT; - - /* - * We must make sure the anon_vma is allocated - * so that the anon_vma locking is not a noop. - */ - if (unlikely(anon_vma_prepare(vma))) - return -ENOMEM; - anon_vma_lock(vma); - - /* - * vma->vm_start/vm_end cannot change under us because the caller - * is required to hold the mmap_sem in read mode. We need the - * anon_vma lock to serialize against concurrent expand_stacks. - */ - address += 4 + PAGE_SIZE - 1; - address &= PAGE_MASK; - error = 0; - - /* Somebody else might have raced and expanded it already */ - if (address > vma->vm_end) { - unsigned long size, grow; - - size = address - vma->vm_start; - grow = (address - vma->vm_end) >> PAGE_SHIFT; - - error = acct_stack_growth(vma, size, grow); - if (!error) - vma->vm_end = address; - } - anon_vma_unlock(vma); - return error; -} -#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ - -#ifdef CONFIG_STACK_GROWSUP -int expand_stack(struct vm_area_struct *vma, unsigned long address) -{ - return expand_upwards(vma, address); -} - -struct vm_area_struct * -find_extend_vma(struct mm_struct *mm, unsigned long addr) -{ - struct vm_area_struct *vma, *prev; - - addr &= PAGE_MASK; - vma = find_vma_prev(mm, addr, &prev); - if (vma && (vma->vm_start <= addr)) - return vma; - if (!prev || expand_stack(prev, addr)) - return NULL; - if (prev->vm_flags & VM_LOCKED) { - make_pages_present(addr, prev->vm_end); - } - return prev; -} -#else -/* - * vma is the first one with address < vma->vm_start. Have to extend vma. - */ -int expand_stack(struct vm_area_struct *vma, unsigned long address) -{ - int error; - - /* - * We must make sure the anon_vma is allocated - * so that the anon_vma locking is not a noop. - */ - if (unlikely(anon_vma_prepare(vma))) - return -ENOMEM; - anon_vma_lock(vma); - - /* - * vma->vm_start/vm_end cannot change under us because the caller - * is required to hold the mmap_sem in read mode. We need the - * anon_vma lock to serialize against concurrent expand_stacks. - */ - address &= PAGE_MASK; - error = 0; - - /* Somebody else might have raced and expanded it already */ - if (address < vma->vm_start) { - unsigned long size, grow; - - size = vma->vm_end - address; - grow = (vma->vm_start - address) >> PAGE_SHIFT; - - error = acct_stack_growth(vma, size, grow); - if (!error) { - vma->vm_start = address; - vma->vm_pgoff -= grow; - } - } - anon_vma_unlock(vma); - return error; -} - -struct vm_area_struct * -find_extend_vma(struct mm_struct * mm, unsigned long addr) -{ - struct vm_area_struct * vma; - unsigned long start; - - addr &= PAGE_MASK; - vma = find_vma(mm,addr); - if (!vma) - return NULL; - if (vma->vm_start <= addr) - return vma; - if (!(vma->vm_flags & VM_GROWSDOWN)) - return NULL; - start = vma->vm_start; - if (expand_stack(vma, addr)) - return NULL; - if (vma->vm_flags & VM_LOCKED) { - make_pages_present(addr, start); - } - return vma; -} -#endif - -/* - * Ok - we have the memory areas we should free on the vma list, - * so release them, and do the vma updates. - * - * Called with the mm semaphore held. - */ -static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) -{ - /* Update high watermark before we lower total_vm */ - update_hiwater_vm(mm); - do { - long nrpages = vma_pages(vma); - - mm->total_vm -= nrpages; - if (vma->vm_flags & VM_LOCKED) - mm->locked_vm -= nrpages; - vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); - vma = remove_vma(vma); - } while (vma); - validate_mm(mm); -} - -/* - * Get rid of page table information in the indicated region. - * - * Called with the mm semaphore held. - */ -static void unmap_region(struct mm_struct *mm, - struct vm_area_struct *vma, struct vm_area_struct *prev, - unsigned long start, unsigned long end) -{ - struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; - struct mmu_gather *tlb; - unsigned long nr_accounted = 0; - - lru_add_drain(); - tlb = tlb_gather_mmu(mm, 0); - update_hiwater_rss(mm); - unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); - vm_unacct_memory(nr_accounted); - free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, - next? next->vm_start: 0); - tlb_finish_mmu(tlb, start, end); -} - -/* - * Create a list of vma's touched by the unmap, removing them from the mm's - * vma list as we go.. - */ -static void -detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, - struct vm_area_struct *prev, unsigned long end) -{ - struct vm_area_struct **insertion_point; - struct vm_area_struct *tail_vma = NULL; - unsigned long addr; - - insertion_point = (prev ? &prev->vm_next : &mm->mmap); - do { - rb_erase(&vma->vm_rb, &mm->mm_rb); - mm->map_count--; - tail_vma = vma; - vma = vma->vm_next; - } while (vma && vma->vm_start < end); - *insertion_point = vma; - tail_vma->vm_next = NULL; - if (mm->unmap_area == arch_unmap_area) - addr = prev ? prev->vm_end : mm->mmap_base; - else - addr = vma ? vma->vm_start : mm->mmap_base; - mm->unmap_area(mm, addr); - mm->mmap_cache = NULL; /* Kill the cache. */ -} - -/* - * Split a vma into two pieces at address 'addr', a new vma is allocated - * either for the first part or the the tail. - */ -int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, - unsigned long addr, int new_below) -{ - struct mempolicy *pol; - struct vm_area_struct *new; - - if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK)) - return -EINVAL; - - if (mm->map_count >= sysctl_max_map_count) - return -ENOMEM; - - new = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); - if (!new) - return -ENOMEM; - - /* most fields are the same, copy all, and then fixup */ - *new = *vma; - - if (new_below) - new->vm_end = addr; - else { - new->vm_start = addr; - new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); - } - - pol = mpol_copy(vma_policy(vma)); - if (IS_ERR(pol)) { - kmem_cache_free(vm_area_cachep, new); - return PTR_ERR(pol); - } - vma_set_policy(new, pol); - - if (new->vm_file) - get_file(new->vm_file); - - if (new->vm_ops && new->vm_ops->open) - new->vm_ops->open(new); - - if (new_below) - vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + - ((addr - new->vm_start) >> PAGE_SHIFT), new); - else - vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); - - return 0; -} - -/* Munmap is split into 2 main parts -- this part which finds - * what needs doing, and the areas themselves, which do the - * work. This now handles partial unmappings. - * Jeremy Fitzhardinge <jeremy@goop.org> - */ -int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) -{ - unsigned long end; - struct vm_area_struct *vma, *prev, *last; - - if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) - return -EINVAL; - - if ((len = PAGE_ALIGN(len)) == 0) - return -EINVAL; - - /* Find the first overlapping VMA */ - vma = find_vma_prev(mm, start, &prev); - if (!vma) - return 0; - /* we have start < vma->vm_end */ - - /* if it doesn't overlap, we have nothing.. */ - end = start + len; - if (vma->vm_start >= end) - return 0; - - /* - * If we need to split any vma, do it now to save pain later. - * - * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially - * unmapped vm_area_struct will remain in use: so lower split_vma - * places tmp vma above, and higher split_vma places tmp vma below. - */ - if (start > vma->vm_start) { - int error = split_vma(mm, vma, start, 0); - if (error) - return error; - prev = vma; - } - - /* Does it split the last one? */ - last = find_vma(mm, end); - if (last && end > last->vm_start) { - int error = split_vma(mm, last, end, 1); - if (error) - return error; - } - vma = prev? prev->vm_next: mm->mmap; - - /* - * Remove the vma's, and unmap the actual pages - */ - detach_vmas_to_be_unmapped(mm, vma, prev, end); - unmap_region(mm, vma, prev, start, end); - - /* Fix up all other VM information */ - remove_vma_list(mm, vma); - - return 0; -} - -EXPORT_SYMBOL(do_munmap); - -asmlinkage long sys_munmap(unsigned long addr, size_t len) -{ - int ret; - struct mm_struct *mm = current->mm; - - profile_munmap(addr); - - down_write(&mm->mmap_sem); - ret = do_munmap(mm, addr, len); - up_write(&mm->mmap_sem); - return ret; -} - -static inline void verify_mm_writelocked(struct mm_struct *mm) -{ -#ifdef CONFIG_DEBUG_VM - if (unlikely(down_read_trylock(&mm->mmap_sem))) { - WARN_ON(1); - up_read(&mm->mmap_sem); - } -#endif -} - -/* - * this is really a simplified "do_mmap". it only handles - * anonymous maps. eventually we may be able to do some - * brk-specific accounting here. - */ -unsigned long do_brk(unsigned long addr, unsigned long len) -{ - struct mm_struct * mm = current->mm; - struct vm_area_struct * vma, * prev; - unsigned long flags; - struct rb_node ** rb_link, * rb_parent; - pgoff_t pgoff = addr >> PAGE_SHIFT; - int error; - - len = PAGE_ALIGN(len); - if (!len) - return addr; - - if ((addr + len) > TASK_SIZE || (addr + len) < addr) - return -EINVAL; - - flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; - - error = arch_mmap_check(addr, len, flags); - if (error) - return error; - - /* - * mlock MCL_FUTURE? - */ - if (mm->def_flags & VM_LOCKED) { - unsigned long locked, lock_limit; - locked = len >> PAGE_SHIFT; - locked += mm->locked_vm; - lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; - lock_limit >>= PAGE_SHIFT; - if (locked > lock_limit && !capable(CAP_IPC_LOCK)) - return -EAGAIN; - } - - /* - * mm->mmap_sem is required to protect against another thread - * changing the mappings in case we sleep. - */ - verify_mm_writelocked(mm); - - /* - * Clear old maps. this also does some error checking for us - */ - munmap_back: - vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); - if (vma && vma->vm_start < addr + len) { - if (do_munmap(mm, addr, len)) - return -ENOMEM; - goto munmap_back; - } - - /* Check against address space limits *after* clearing old maps... */ - if (!may_expand_vm(mm, len >> PAGE_SHIFT)) - return -ENOMEM; - - if (mm->map_count > sysctl_max_map_count) - return -ENOMEM; - - if (security_vm_enough_memory(len >> PAGE_SHIFT)) - return -ENOMEM; - - /* Can we just expand an old private anonymous mapping? */ - if (vma_merge(mm, prev, addr, addr + len, flags, - NULL, NULL, pgoff, NULL)) - goto out; - - /* - * create a vma struct for an anonymous mapping - */ - vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); - if (!vma) { - vm_unacct_memory(len >> PAGE_SHIFT); - return -ENOMEM; - } - - vma->vm_mm = mm; - vma->vm_start = addr; - vma->vm_end = addr + len; - vma->vm_pgoff = pgoff; - vma->vm_flags = flags; - vma->vm_page_prot = protection_map[flags & - (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; - vma_link(mm, vma, prev, rb_link, rb_parent); -out: - mm->total_vm += len >> PAGE_SHIFT; - if (flags & VM_LOCKED) { - mm->locked_vm += len >> PAGE_SHIFT; - make_pages_present(addr, addr + len); - } - return addr; -} - -EXPORT_SYMBOL(do_brk); - -/* Release all mmaps. */ -void exit_mmap(struct mm_struct *mm) -{ - struct mmu_gather *tlb; - struct vm_area_struct *vma = mm->mmap; - unsigned long nr_accounted = 0; - unsigned long end; - -#ifdef arch_exit_mmap - arch_exit_mmap(mm); -#endif - - lru_add_drain(); - flush_cache_mm(mm); - tlb = tlb_gather_mmu(mm, 1); - /* Don't update_hiwater_rss(mm) here, do_exit already did */ - /* Use -1 here to ensure all VMAs in the mm are unmapped */ - end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); - vm_unacct_memory(nr_accounted); - free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); - tlb_finish_mmu(tlb, 0, end); - - /* - * Walk the list again, actually closing and freeing it, - * with preemption enabled, without holding any MM locks. - */ - while (vma) - vma = remove_vma(vma); - - BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); -} - -/* Insert vm structure into process list sorted by address - * and into the inode's i_mmap tree. If vm_file is non-NULL - * then i_mmap_lock is taken here. - */ -int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) -{ - struct vm_area_struct * __vma, * prev; - struct rb_node ** rb_link, * rb_parent; - - /* - * The vm_pgoff of a purely anonymous vma should be irrelevant - * until its first write fault, when page's anon_vma and index - * are set. But now set the vm_pgoff it will almost certainly - * end up with (unless mremap moves it elsewhere before that - * first wfault), so /proc/pid/maps tells a consistent story. - * - * By setting it to reflect the virtual start address of the - * vma, merges and splits can happen in a seamless way, just - * using the existing file pgoff checks and manipulations. - * Similarly in do_mmap_pgoff and in do_brk. - */ - if (!vma->vm_file) { - BUG_ON(vma->anon_vma); - vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; - } - __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); - if (__vma && __vma->vm_start < vma->vm_end) - return -ENOMEM; - if ((vma->vm_flags & VM_ACCOUNT) && - security_vm_enough_memory(vma_pages(vma))) - return -ENOMEM; - vma_link(mm, vma, prev, rb_link, rb_parent); - return 0; -} - -/* - * Copy the vma structure to a new location in the same mm, - * prior to moving page table entries, to effect an mremap move. - */ -struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, - unsigned long addr, unsigned long len, pgoff_t pgoff) -{ - struct vm_area_struct *vma = *vmap; - unsigned long vma_start = vma->vm_start; - struct mm_struct *mm = vma->vm_mm; - struct vm_area_struct *new_vma, *prev; - struct rb_node **rb_link, *rb_parent; - struct mempolicy *pol; - - /* - * If anonymous vma has not yet been faulted, update new pgoff - * to match new location, to increase its chance of merging. - */ - if (!vma->vm_file && !vma->anon_vma) - pgoff = addr >> PAGE_SHIFT; - - find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); - new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, - vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); - if (new_vma) { - /* - * Source vma may have been merged into new_vma - */ - if (vma_start >= new_vma->vm_start && - vma_start < new_vma->vm_end) - *vmap = new_vma; - } else { - new_vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); - if (new_vma) { - *new_vma = *vma; - pol = mpol_copy(vma_policy(vma)); - if (IS_ERR(pol)) { - kmem_cache_free(vm_area_cachep, new_vma); - return NULL; - } - vma_set_policy(new_vma, pol); - new_vma->vm_start = addr; - new_vma->vm_end = addr + len; - new_vma->vm_pgoff = pgoff; - if (new_vma->vm_file) - get_file(new_vma->vm_file); - if (new_vma->vm_ops && new_vma->vm_ops->open) - new_vma->vm_ops->open(new_vma); - vma_link(mm, new_vma, prev, rb_link, rb_parent); - } - } - return new_vma; -} - -/* - * Return true if the calling process may expand its vm space by the passed - * number of pages - */ -int may_expand_vm(struct mm_struct *mm, unsigned long npages) -{ - unsigned long cur = mm->total_vm; /* pages */ - unsigned long lim; - - lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; - - if (cur + npages > lim) - return 0; - return 1; -} |